The invention relates generally to cooling devices, and more particularly, to a cooling device having integrated millichannels for a power module.
Power electronics refers to the application of solid-state electronics related to the control and conversion of electrical power. This conversion is typically performed by silicon, silicon carbide, and gallium nitride devices that are packaged into power modules. One of the factors associated with the power modules is the generation of heat. While the heat generated by the power modules is due to many factors, it generally relates to the fact that the power module efficiency is always less than 100 percent, and the efficiency loss is typically generated as heat. Unfortunately, the power module performance tends to erode with increased temperatures.
An additional factor for thermal management relates to the packaging of a number of devices in small footprints. The power density, at which the devices, and thus the module can operate, therefore depends on the ability to remove this generated heat. The common form of thermal management of power electronics is through heat sinks. Heat sinks operate by transferring the heat away from the heat source of the power module, thereby maintaining the heat source at a lower relative temperature. There are various types of heat sinks known in the thermal management field including air-cooled and liquid-cooled devices.
One example of the thermal management of a power module includes the attachment of a heat sink with embedded tubes to provide liquid cooling of the power module. The heat sink is typically a metallic structure, such as aluminum or copper. A cooling medium such as water is passed through the tubes to cool the power module. The heat sink is typically coupled to the power module base with a thermal interface material (TIM) dispersed there between. The thermal interface material may comprise thermal greases, compliant thermal pads, or the like. The conventional cooling devices have large thermal gradients and high-pressure drops across the devices. Also, the conventional cooling devices have large thermal resistance, which limits operation levels of the power module.
There is a need for an improved cooling device.